Oxidation reactions of organic compounds and in particular the Bayer-Villiger reaction is of considerable interest in order to convert readily available carbonyl compounds in more complex and valuable products.
The use of peroxyacetic acid in the Baeyer-Villiger oxidation as described in Justus Liebigs Ann. Chem. 681 (1965), pages 28-30 is a common method for the oxidation of ketones to the respective lactones. However, the use of peroxyacetic acid involves considerable disadvantages regarding cost-effectiveness and safety aspects, in particular in industrial-scale processes.
In Nature 412 (2001), pages 423-425, and in Journal of Catalysis 234 (2005), pages 96-100, a tin-containing zeolite Beta is described for the use in the Baeyer-Villiger reaction. Further, in Journal of Catalysis 234 (2005), pages 96-100, a Baeyer-Villiger reaction is disclosed wherein citral is used as starting material. The experiments carried out regarding this reaction show that by use of the tin-containing zeolite Beta a selectivity to melonal of at most 20% is achieved. Generally, tin-containing zeolite Beta materials are comparatively difficult to prepare which renders this prior art process disadvantageous since the synthesis of the catalyst, disclosed in U.S. Pat. No. 5,968,473 and U.S. Pat. No. 6,306,364, it is technically difficult to scale-up due to low yield, high synthesis times more than 15 days, the use of HF and chlorinated Sn precursor compounds.
Furthermore, in Microporous and Mesoporous Materials 165 (2013), pages 210-218, the use of a tin-containing zeolitic material having an MWW framework structure in the Baeyer-Villiger reaction of 2-adamantanone is described. According to this document, the zeolitic materials are obtained from a boron-containing precursor material which is not subjected to deboronation resulting in a material having a comparatively high boron content.
WO 03/074422 A1 and U.S. Pat. No. 7,326,401 B2 describe a process for synthesizing a zeolite material having MWW structure. A tin containing MWW is mentioned in the description, having a very high tin loading of about 4.7 weight-%. This tin containing MWW is prepared from a B-MWW zeolite precursor which is deboronated by acid treatment before the Sn is introduced.